Dust protector device



March 28, 1933. J. F. MARTIN DUST PROTECTOR DEVICE Filed Feb. 26, 1931 A INVENTOR 6/) E/farf/O BY wlw ATTORNEY Patented Mar. 28, 1933 UNITED TAT S JOHN F. MARTIN, OF SPRINGFIELD, MASSACHUSETTS, Assmivon To UN ED AME ICAN BOSCH CORPORATION, or SPRINGFIELD,

NEW YORK PAT ENT; OFFICE"...

'MASSAGHUSETTS, A CORPOBIATIOIN'VI, or

DUST PROTECTOR DEVICE Application filed February 2s ,'19s1 .-f Serial No. 518,482.

This invention comprises improvements in protective devices, and especially means for safeguarding mechanism against the entrance of dust andthus prevent the injurious efiects which dust will always produce.

It is an object of the invention to provide simple and effective means for sealing the casing or housing of virtually any type of enclosed apparatus having moving parts operated by a project-ing drive shaft, at t e place where said shaft enters the casing or housing, and to arrange the sealing means so that the desired result will not be lessened by wear due to long continued use.

A further object is to provide sealing means including a member carried by the projecting drive shaft of an enclosed mechanical apparatus, at the place where the shaft enters the casing or housing of the latter, and a portion of said casing or housing that is designed to cooperate with said member to bring about the full dustexcluding action.

Another object of the invention is to provide a dust protector which can be utilized with enclosed apparatus as above set forth, and which will serve the purpose of not only obstructing the admission of dust to the interior of the casing. or housing, but also of trapping the dust in suitable recesses, which can readily be emptied, so that the dust protector can easily be kept clean.

The nature of the invention and the peculiar merit and advantages thereof are explained in the following description and accompanying drawing, which show a number of embodiments of my protective devices; The disclosure, however, is illustrative only, and I may make alterations in the various parts within the scope and meaning of the broad terms in which the novel features of the invention are defined.

On said drawing,

Fig. 1 is a side view, partly in section, of one form of my invention; and Fig. 2 is a vertical transverse section on the line 22 of Fig. 1. 7

The same numerals identify the same parts throughout.

In the particular description of what the drawing presents, Iemploy the numeral 1 to indicate'the body of an electrical magneto such as is commonly used to furnish ignition current for'internal combustion engines.

The magneto has an end plate 2, and is drivenby a shaft 3,'-which is connected with the armature of the magneto through a so- .called impulse coupling 4. This coupling,

as is wellknowm-is constructed so that. it hasfno effect at the regular speed, but in starting it causesthe armature to bemomentarily retarded and then thrownfOrward with an accelerated motion to generate enough energy for the spark. This impulse coupling has a casing orhousing, part of which is depicted at 5, aflixed to "or made integral with the end plate '2. Magnetos with such couplings'are generally much exposedto dust and'di'rt, and it-is quite important and desirable to protect the couplings, as well as the inside'of the magneto,

which usually has its armature chamber in line therewith. The part 5 of the casing has a reduced terminal rim with an exterior h shoulder 6, and the remainder of the casing is in the form of two semi-cylindrical'halves 7,-with a reduced rim and interior annular shoulder 8. The rim with the shoulder 8 fits upon the rim of the part 5, and two and cause them to grip the reducedrim of the part 5 securely, tom'ak'e the housingof the coupling complete. The halves or sections 7 can thus be quickly assembled with the part 5 around theishaft3, and, can be dismounted whenever necessary merely by taking out the bolts 9; g

The part ofthe casing made up of the sections 7 has a reduced extension 10 within which is a spiral spring elementll held fast to the casing by a rivet 12. Surrounding the shaft within this extension is a member or packing sleeve 13 of felt or some other'material, and the free end of the spring 11 surrounds and presses upon this packing. The front of the extension is closed by, a wall 14,

I having an opening 15 through which the shaft-3 passes. The spring 11 is of the clock I. a I i type; it is light in weight, and in rest position it exerts very little pressure on the pack- 7 ing. It is disposed in the casing in such position that, when the shaft 3 rotates in the direction of the arrow in Fig. 2, the tendency is to wind up and tighten this spring. Of course, the sleeve 13 is loose upon theshaft ,3, but the shaft will exert a turning force thereon due to friction, and it may rotate therewith toa slight eXtentQ But assoon as the turning of the sleeve windsup the spring tight enough, the spring holds the sleeve stationary. Hence a perfect sealing is obtained, and is not diminished by the wear of the packing. The edge ofthe pack- 7 ing is also held by the spring firmly against the inner face of the wall 14; and thus the housing for the coupling .4 is closed perfectly. v To afiix the sections 7 more surely upon. the part 5 of the housing of the coupling, may further attach to this part and to the sections alined lugs 16, with openings for bolts 17. These bolts will hold the sections 7 to the part 5 more securely than the bolts 9.

Obviously, my invention can be practiced with any enclosed mechanism, and a magneto with its encased impulse coupling is mentioned above only by. Way of example.

Having described my invention, what I claim is z 1. A protective device forapparatus arranged in an enclosing casing, with a rotary shaft entering vthe casing to drive said apparatus, said device including a member on the shaft and an element afiixed within the casing adjacent one end and encircling said member adjacent the opposite end tobe put under stress when the shaft revolves to cause the member to engage the shaft tightly and seal said casing.

2. A protective device for mechanismenclosed in, a casing and having a rotary shaft entering the casing to operate said mechanism, said device comprising a packing sleeve on the shaft Within the casing at the place where the shaft enters the latter, and a spring attached at one end tothe inside of r the casing, and encircling the packing at its opposite end to cause the packing to seal the casing. r 3. A protective device for mechanism contained in an enclosing casing and having a tained in an enclosing casing and having a rotary shaft projecting into the latter to operate said mechanism, said device comprising a packing sleeve on the shaft inside the casing where the shaft enters the latter, a coilspring engaging the inside of the easing at one end and encircling the sleeve at the other end and arranged so that the rotation of the shaft tends to make the sleeve wind up the spring and the spring depress the sleeve against the shaft to seal the casing.

5. A protective device for apparatus ar-.

ranged in an enclosing casing, with a rotary shaft entering the casing to drive said apparatus, said device including a packing member on the shaft'in the casing adjacent where the shaft enters the latter, and a yielding element engaging the casing at one end and encircling said member adjacent the other end to cause said member to en-,

gage said shaft tightly and seal the casing when the shaft revolves. j

In testimony'whereof I aflix my signature. Y

JOHN MARTIN.

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